1. Field of the Invention
The present invention concerns a device and a method for isolating and cultivating live cells on a filter or extracting amplified genetic material from live cells isolated on a filter. It applies in particular to isolating and cultivating particular cells present in a liquid, especially blood, or extracting the genetic material of those particular cells.
2. Description of the Related Art
Some particular blood cells, for example tumor cells and trophoblasts, are present in very small proportions and must be counted for a cytological analysis. However, compared to most of the other cells present in blood, they have a greater size.
It is known to apply a formaldehyde-based fixing buffer to a blood sample to fix the cells searched for and then to pass the resulting liquid into a porous filter. That filter is then used to examine the cells searched for thereon under a microscope in the laboratory. However, this procedure does not make it possible to obtain live cells.
Now, the inventor has determined that obtaining live cells would make it possible to envisage the identification of specific markers and to obtain good conditions for applying molecular biology, cytogenetic and fluorescence in situ hybridization (FISH) techniques to diagnose genetic abnormalities in tumor cells or trophoblastic cells.
The present invention aims to remedy these drawbacks and to address this requirement by making it possible, under conditions compatible with routine laboratory examination, to collect live cells that can subsequently be cultivated in appropriate media in the presence of appropriate growth factors.
The present invention also concerns extracting amplified genetic material from cells isolated on a filter and detecting mutations and levels of expression of genes coding for sensitivity and resistance to target therapies or genetic abnormalities.
It applies in particular to collecting and uniformly amplifying DNA or RNA from particular cells present in a liquid, especially blood.
It is known, for example from the document PCT/FR 2006/000562, to apply a formaldehyde-based fixing buffer to a blood sample to fix the cells searched for and then to pass the resulting liquid into a porous filter. That filter is then analyzed under a microscope in the laboratory to look for the cells. The cells can then be sampled on the filter for analysis, for example by a genetic analysis.
However, this procedure cannot be reproduced on a large scale and at a reasonable cost because of the time, equipment and precise working that it entails. Such reproduction on a large scale and at lower cost would make it possible to carry out molecular biology analyses both on tumor cells and on trophoblastic cells.